Among viruses, human immunodeficiency virus (hereafter, referred to as HIV), a kind of retrovirus, is known to cause acquired immunodeficiency syndrome (hereafter, referred to as AIDS). The therapeutic agent for AIDS is mainly selected from a group of reverse transcriptase inhibitors (e.g., AZT, 3TC) and protease inhibitors (e.g., Indinavir), but they are proved to be accompanied by side effects such as nephropathy and the emergence of resistant viruses. Thus, the development of anti-HIV agents having the other mechanism of action has been desired.
On the other hand, currently, a combination therapy is reported to be efficient in treatment for AIDS because of the frequent emergence of the resistant mutant. Two kinds of reverse transcriptase inhibitors and protease inhibitors are clinically used as an anti-HIV agent; however agents having the same mechanism of action often exhibit cross-resistance or only an additional activity. Therefore, development of anti-HIV agents having the other mechanism of action is desired.
Under the circumstances above, an integrase inhibitor has been focused on as an anti-HIV agent having a novel mechanism of action (Ref: Patent Documents 1 and 2). As an anti-HIV agent having such a mechanism of action, known are carbamoyl-substituted hydroxypyrimidinone derivative (Ref: Patent Documents 3 and 4) and carbamoyl-substituted hydroxypyrrolidione derivative (Ref: Patent Document 5). Further, a patent application concerning carbamoyl-substituted hydroxypyridone derivative has been filed (Ref: Patent Document 6, Example 8).
Other known carbamoylpyridone derivatives include 5-alkoxypyridine-3-carboxamide derivatives and γ-pyrone-3-carboxamide derivatives, which are a plant growth inhibitor or herbicide (Ref: Patent Documents 7-9).
Other HIV integrase inhibitors include N-containing condensed cyclic compounds (Ref: Patent Document 10).
In addition, the present applicant filed a dicyclic carbamoylpyridone derivative as a HIV integrase inhibiting agent (Ref: Patent Document 11).    [Patent Document 1] WO03/016275    [Patent Document 2] WO2004/024693    [Patent Document 3] WO03/035076    [Patent Document 4] WO03/035076    [Patent Document 5] WO2004/004657    [Patent Document 6] JP Patent Application 2003-32772    [Patent Document 7] JP Patent Publication 1990-108668    [Patent Document 8] JP Patent Publication 1990-108683    [Patent Document 9] JP Patent Publication 1990-96506    [Patent Document 10] WO2005/016927    [Patent Document 11] WO2006/088173